In order to squish Loot, it must be unzapped, right? So basically this curse should be played on a zapped Loot, then your opponent is stuck with this Loot and cannot squish it unless he can find a way to remove the curse, right?

You must zap a Loot card in order to squish it yourself. It would be legal to play Curse of Quack on Loot that is zapped or unzapped, though as you point out, if the loot is already zapped, it will prevent the owner from squishing it immediately.

You must zap a Loot card in order to squish it yourself. It would be legal to play Curse of Quack on Loot that is zapped or unzapped, though as you point out, if the loot is already zapped, it will prevent the owner from squishing it immediately.

Side question - Zapping to squish doesn’t also allow the zapped ability, if applicable, to trigger as well, right?

Back to original point, how could one maximize the effect of Curse of Quack? In other words, what’s the best way to play it to ensure one’s opponent has a wasted hoard slot so to speak for as many turns as possible?

how could one maximize the effect of Curse of Quack? In other words, what’s the best way to play it to ensure one’s opponent has a wasted hoard slot so to speak for as many turns as possible?

The best use of this curse that I have found is to stick it to the Hot Potato after zapping it and sending it to my opponent's hoard, thus giving him a permanent potato. I have a Wizard deck built around this fun combo.

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-Brandon Murphy
MiB 0787

"I wouldn't even take a whiz on this! I used to DREAM of taking a whiz on this!" - The Monarch

Side question - Zapping to squish doesn’t also allow the zapped ability, if applicable, to trigger as well, right?

No, you must Zap the card to activate a Zap ability, and you must Zap the card to squish it. Think of the Zap as the cost to do those things. You can't pay it twice, and you can't activate them simultaneously.